Automatic stereoplotting system and method



Aug. 18, 1964 G. L. HoBRouGH 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM AND' METHOD Filed Aug. '7, 1961 19 Sheets-Sheet 1 lnven tor GILBERT L. HOBROUGH Allg- 18, 1954 G. L. HoBRouGH AUTOMATIC sTEREoPLoTTING sTsTEM AND METHOD Filed Aug. 7, 1961 19 Sheets-Sheet 2 Aug. 18, 1964 G. l.. HoBRoUGH AuToMATIc sTEREoPLoTTING SYSTEM AND METHOD 19 Sheets-Sheet .3

Filed Aug. 7 1961 2N w. w New .ssl

Inventor GILBERT l.. HoBRouGH by: W

Aug- 18 1954 G. L. HoBRouGl-l 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 Sheets-Sheet 4 IMAGE OF SCANNING SPOT 32 X PARALLAX x ERROR f z MOTION TO ,y cORREcT FOR A A vlEwlNG PLATEN OF i `X746 x RARALLAx CONVENTIONAL STEREO PLOTTER /g 24 FLUORESCENT SCREEN Inventor GILBERT L. HOBROUGH Aug. 18, 1964 G. L. HoBRoUGH 3,145,303

AUTOMATIC sTEREoPLoTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 Sheets-Shea?l 5 WAVEFORM AT H TYPICAL wAvEFoRM AT D oR E FIG. 6

TYPICAL WAVEF ORM AT F 0R G F /G.7

FIG. 8

53 37 5I l f N 55 P 56 o RIGHT l SIGNAL 'MAGE FILTER sIGNAL Low SCAN 1I 54 MULTIPLIER f PASS OUTLET 4/ FILTER LEFT ,MAGE sIGNAL SIGNAL FILTER F /G- 9 scAN I Inventor GILBERT L. HOBROUGH A118'- 18, 1964 G. L.. HoBRoUGH 3,145,303

AUTOMATIC sTEREoPLoTTING SYSTEM AND METHOD Filed Aug. '7 1961 19 Sheets-Sheet 6 IMAGES ALIGNED IMAGEIS MISALIGNED I N l N I I MIsALIGNMENT-I L..

| O Il l IDEAL BOUNDARY WAVEFORM EFFECT OF FIN/TE SPOT.

EFFECT oF HIGH AND Low PAss FILTERS.

FIG. Il

Inventor GILBERT L. HoBRouGH Aug. 18, 1964 SCAN I LEFT IMAGE SIGNAL SCAN 1I RIGHT IMAGE SIGNAL IMAGES ALIGNED AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. '7 1961 19 Sheets-Sheet 7 FILTER LEFT LEADING RIGHT o eI 62 i L RE w REGISTRATION ERROR SIGNAL F G. I2

LEFT Fam/ING l RIGI-IT Inventor GILBERT L. HOBROUGH A118 18, 1954 cus. L. HoBRoUGH 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 'I 1961 19 sheets-sheet 8 SCAN I 63 67 LEFT IMAGE sIGNAL FILTER /To TI 38 Low REGIsTRAnoN PAss ERRoR 37 64\ FILTER SIGNAL FILTER 69 scANu l RIGHT FIG IMAGE SIGNAL 66 68 IoI 99 Ios "x" REF f X X L.P.F. PA RALLAX EXJ REGISTRATION `SIGNAL I ERROR SIGNAL S 98 ,06

II II Y\` Y "Y"REE x L.P,F. PARALLAx j SIGNAL Io2 Ioo Io4 FIG. l5

Inventor GILBERT L. HOBROUGH Aug- 18, 1964 G. I.. HoBRouGH 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM .AND METHOD Filed Aug. 'I 1961 19 sheets-sheet 9 GT S7 SERvo 9 o 9 92 SWITCHES cORRELATION ONTSION C'RCUTRY 3S kas SI 93 S 95 96 97 AMR R- A-l RIGHT IMAGE SIGNAL "Y" PA'RALLAx SIGNAL T'IsG-ISTR-ATNJ l I PTA ALLAx:

I OISORIMINATORI ANALYSERI LEFT IMAGE SIGNAL 8 1--1rr-r\l50 29 PHASE I Io IIa 37 PHOTO A 126 )33 ,Npgghc-UON t o CELLS l Il I TI 27 '-PHOTOGRAPHIc ANALYSER SIGNA'- 3' l,'TRANSRARENOIES y.. TRAcING I`2O2 LENSES @l `33 RF DRIVE TSM v l SIGNAL SIGNAL I "Y" Io7\\ I2I 'MOTOR 26e RE scANNING SERvO cAIHODE 23 22 GENERATOR AMI? ,4 RAY TUBE I '27 I I "x"OER EOTION SIGNAL I Y T "Y' DEFLEOTTON SIGNAL Sia/:O n 'x" OR 'Y' ,29 MOTOR OR I4O /G. ,6. BOOR I' T T A cOSSDRIvE DIRECTION A TRACING SIGNAL I SIGNAL A SIN 9DRIVE+ DIRECTION DISTRIBUTOR o '33 l PHASE INI-ORMATION ITI 57 if" L SLOPE ISD ,59 B ANAUSER IS'GNALN 16o A SING+ I?, cpSG Y DRIVE SIGNAL II Il ERROR I l /-I58 BXSPATE SIGNAL S'GNA'- SIGNAL SIGNAL I STRIBUTOR B SIN G ERROR+DIRECTION L B COS O "Y"ERROR+DIRECTION II3 \IGI T Inventor GILBERT L. HoBRoUGH Aug. 18, 1964 G. L. HoBRoUGH 3,145,303

AUTOMATIC sTEREoPLoTTTNG SYSTEM AND METHOD Filed Aug. '7 1961 19 Sheets-Sheet 10 SCAN I Inventor GILBERT L. HoBRouGH Aug. 18, 1964 G. l.. HoBRoUGH AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 7 1961 19. Sheets-Sheet 11 a .mi om Nom o 9 9 ms a f y E AV e O O o 3 o o /lj f om H non N H 25m mm Sm Inventor GILBERT L. HoBRoUGH Aug 18, 1964 G. L. HoBRouGH 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 Sheets-Sheet 12 BLUE FILTER U BLUE LIGHT 3'3 /LAMP FROM CRT PHOTO ELECTRIC CELL D/cHRo/c MIRROR- RED OR GREEN l' ANAGL YPH FILTER coNDENsER LENS Ik L RED 0R GREEN vlEw/NG M LIGHT FROM LIGHT souRcE Inventor GILBERT L. HOBROUGH by.' W f/yam Allg 13, 1964 G. L. HOBROUGH AUTOMATIC sTEREoPLoTTING SYSTEM AND METHOD 19 Sheets-Sheet 15 Filed Aug. '7

Inventor GILBERT L. HoeRouGH Aug. 18, 1964 G. L. HoBRoUGH 3,145,303

AUTOMATIC sTEREoPLoTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 sheets-sheet 14 [11g/111111111lll/111111ZI g Inventor GILBERT l.. HOBROUGH by.- @wmf/vm.

Aug. 18, 1964 G. l.. HoBRoUGH AUTOMATIC sTERx-:oPLoTTTMG sYsTEM AND METHOD Filed Aug. '7 1961 19 Sheets-Sham*I 15 M m m 0 l FIG. 25

Inventor GILBERT L. HOBROUGH Aug. 18, 1964 G. L. HOBROUGH 3,145,303

AUTOMATIC sTEREoPLoTTTNG sTsTEM AND METHOD Filed Aug. 7 1961 19 Sheets-Sheet 16 'Y'DRNE "Y'BAR "X"BAR+ FIG' 30 /nvenlor GILBERT L. HoBRoUGH Aug' 18 1964 G. L.. HoBRoUGH AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 Sheecs-Sheei'l 17 FIG. 28

Inventor GILBERT L. HOBROUGH llg- 18 1964 G..L. HoBRoUGH AuToMATIc sTERToPLoTTTNG sYsTEM AND METHOD 19 Sheets-Sheet 18 Filed Aug. 7 1961 Aug. 18, 1964 G. I.. HOBROUGH 3,145,303

AUTOMATIC STEREOPLOTTING SYSTEM AND METHOD Filed Aug. 7 1961 19 Sheets-Sheet 19 "Y" REF.

37 REGISTRATTON ERROR SIGNAL V 85 "Y" PARALLAX l'gE cOORDINATE ERROR SIGNAL REGISTRATION PARALLAx S'G'y RIGHT DISCRIMINATUR v ANALYzER "x"PARALLAx 'MAGE OOOROINATE ERROR S'GNALj SIGNAL 3G 39 aI IIO A ll II x REF j SLOPE TERRAIN 23 los 17I SLOPE ANALYZER MAGNITUDE V TERRAIN SIGNAL SLOPE DIRECTION SIGNALI A 174/1 TRAcING MULTIPLYI NG vELocITY cORRELATOR slGNAL las FIG. 32

82 '08 `SLOPE SIGNAL Irs I93 FROWX" aN'SEl/Ac') uTILIzEO FORM PARALLAx FILTER MuL. OF T.s.M.

MULTIPLIER H0 [73 TSM REE SIGNAL Oc.

'76 AMPLIFIER ,78

90 |86 PHASE [o SHIFT J 179 VP ASE SHIFTTNG RESOL QUAD. I

NET MOTOR I uTILIzED FORM OF n u TSO. SIGNAL L SEM- (SHAFT POSITION) II IS7 I74 F IG 33 Inventor GILBERT L. HOBROUGH United States Patent() 3,145,303 AUTMATC SEEREOPLTHNG SYSTEM AND METHD Giihert irouis Huhrough, Scarborough, Ontarie, iCanada, assigner to Hunting Survey Corporation Limited Filed Aug. 7, i961, Seru'No. 129,583 i9 Elanna. (Cl. 25d-J2e) This invention relates toan automatic sterep plotting system and method for extracting and interpreting image information from stereo photographic pairs and in which substantially eliminates human errors in stereoplotting and automatic contouring photogrammetric techniques in the making of maps and the like.

This application is a continuation-in-part of application Serial No. 77,768, led December 12, 1960, lapsed after the tiling of the instant application and assigned to the same assignee as the present application.

The photogrammetric plotting machine operator must develop unusual skills, many of which are difficult to analyze and define. This is due to the intimate mechanical and interpreting characteristics of the operations performed. The systems and methods of the invention are generally directed to the release of the operator from-the mechanical characteristics of the functions performed by the operator and especially in relation to the operations of sensing and clearing parallax of the stereo images whereby the operator may better concentrate his efforts on interpretative functions. Y

The development of automatic mechanical functions of assistance in stereoplotting is exemplifiedin some detail in a number of prior applications of the present inventor and assigned to the same assignee as the instant application and issued by the United States Patent Oliice under date of December 13, 1960, as numbers: 2,964,639, 2,964,642, 2,964,643 and 2,964,644.

While said prior applications outline both generally and specifically ways and means for accomplishing one or more operations to substitute for efforts of manual and interpretative functions of the operator, investigation of the various techniques has led to the overall organization of substantially automatic operating functions derived from improvements and simplifications of the methods, systems and devices of the prior applications.

lt is accordingly an object of the invention to provide a system and method for sensing parallax by detecting the time difference between the image signals from corresponding parts of each image in such manner as to eliminate magnitude variations, thus to render the system insensitive to change in either the average density or contrast of the stereo images.

It is another object of the invention to provide a system and method as before in which the image signals are unresponsive to image congurations such as lines, circles, and the like and wherein the examination or scanning velocity varies widely thereby to render this system responsive to both fine and coarse image detail.

It is a further object of the invention to provide a substantially automatic stereo photogrammetric system and method in which image signals from a stereographic pair may be translated into as many as up to five separate data signals comprising: an image correlating signal, an X coordinate parallax signal, a Y coordinate parallax signal, a terrain slope magnitude signal, a terrain slope direction signal, a scanning pattern size signal being a function of the terrain slope magnitude signal, and a terrain elevation signal being a function of an X parallax signal for constant Y parallax signal.

It is a further object of the'invention to provide a system and method for plotting topography automatically either by profiling or contouring principles and in which 3,i45,3il3 Fatented Aug. i8, 1964i the terrain conditions control automatically the speed at which profiles or contours are traced.

Having regard to the foregoing, the invention generally contemplates improvements in a stereo image examining system by means of which two image information signals are developed by simultaneously scanning 'the images about a scanning axis. The signals are processed to obtain a registration error signal responsive in magnitude and direction to X and Y coordinate parallax accordingly in the intersection of the images by the scanning axes. A plotting table supports X and Y coordinate bar mechanism freely traversable thereover and including drive motors therefor operating responsive to X and Y coordination in the registrationerror signal whereby a viewing platen supported by a carriage moved by the coordinate bars may be moved over the plotting table responsive 'to the information inthe errorv signal. The viewing platen means is movable in the Z coordinate direction being likewise motor driven and can be caused to move vertically in response to X parallax whereby the viewing platen will achieve a position over the plotting table to eiiect profiling'automatically at a selected X coordinate station along. a Y coordinate direction. In addition the viewing platen may be assumed to be at a tixed height corresponding to a contour of elevation andthe parallax Vinfciirmation utilized to drive the X and Y coordinate bars to etf'ect tracing of a contour at said elevation.

In addition, the invention contemplates the automatic orientation of the stereo images by supportingv them each on three axes about which they may be adjusted in K, phi and omega functions having drivel means for at least one of each and whereby a Y'parallax signal may be selectably employed to drive each of the motors in turn to achieve true orientation without requiring'fvisual inspection by the operator.

The invention also without employing any limitation on the foregoing or deriving limitation therefrom, contemplatesan improvement inia stereoplotting system in which two stereo images are examined and interpreted on a plotting table with the aid of viewing platen means: of cathode ray tube means having screen structure serving as the viewing platen means and adapted to generate a scanning pattern yfor each of the images. A noise gerierator and a fixed frequency source combined to provide a scanning generator adapted to provide a specially desired scanning pattern for-examining the images at the viewingplaten'means. A photo-electric cell associated with each image and including an optical system defines a scanning axis for each image and is adapted vto 'generate an electrical signal responsive to the image information scan. A registration discriminator multiplies and crosscorrelates the signals so provided to develop a registration error signal containing both magnitude and directional information concerning parallax. X and Y drive signals are generated'responsive to'amplitude and 4directional information in said error signal. The viewing platen means may then be moved over the plotting table in X and Y coordinate directions responsive to X and Y coordinate drive signals. In addition, the viewing platen means'may also be moved in a Z coordinate direction responsive to X parallax while restricting X coordinate motion thus to achieve a profiling function. Y

Other objects 'of the invention will be apparent fromV a study of the following specification taken into conjunction with the accompanying drawings.

In the drawings:

FIGURE 1 is a partial electrical schematic of the electronic components of the system of the invention which may be applied to existing stereo plotting devices;

FIGURE 2 is essentially a continuation of FIGURE 1;

FIGURE 3 is a further continuation of FIGURE 1 and 

17. IN A STEREO IMAGE EXAMINING SYSTEM INCLUDING MEANS FOR PROJECTING STEREO IMAGES HAVING X AND Y COORDINATES ONTO VIEWING PLATEN MEANS AND IN WHICH THE IMAGES ARE EXAMINED POINT BY POINT BY ADJUSTING THE INTERSECTION OF THE PROJECTION AXES WITH THE VIEWING PLATEN MEANS TO REMOVE PARALLAX, THE COMBINATION THEREWITH OF: MEANS SUPPORTING EACH OF SAID IMMAGES ROTATABLY ON RESPECTIVE K, PHI AND OMEGA AXES; MEANS FOR ROTATABLY ADJUSTING SAID SUPPORT MEANS ABOUT SAID AXES INCLUDING MOTORS FOR ROTATING SAID SUPPORT MEANS ABOUT AT LEAST ONE EACH OF SAID K, PHI AND OMEGA AXES; AND MEANS FOR SELECTIVELY ENERGIZING SAID MOTORS RESPONSIVE TO PARALLAX IN THE DIRECTION OF ONE OF SAID COORDINATES TO ESTABLISH RELATIVE ORIENTATION OF SAID IMAGES. 